Methionine and cystine requirements of slow- and fast-feathering male broilers from zero to three weeks of age

Auburn University, Poultry Science, Auburn, Alabama 36849, USA.
Poultry Science (Impact Factor: 1.67). 10/2003; 82(9):1423-7. DOI: 10.1093/ps/82.9.1423
Source: PubMed


Two experiments were conducted with fast- (Ross x 3F8) and slow- (Ross x 308) feathering broiler males from 0 to 3 wk of age to determine Met and Cys requirements. A corn-soybean meal basal diet was formulated to be deficient in Met and Cys but was adequate in all other nutrients (22.0% CP; 3,050 kcal ME/kg). In experiment 1, diets contained 0.50% dietary Cys with 0.35, 0.40, 0.45, and 0.50% total Met. Feed conversion (FC) of slow- and fast-feathering males improved in a similar manner to 0.50% Met (linear, P < 0.05). Nitrogen retention measured from 20 to 21 d of age optimized at 0.46% Met (quadratic, P < 0.01), regardless of feathering rate. Experiment 2 examined the response to feeding 0.35, 0.40, 0.45, and 0.50% total Cys in diets having total Met at 0.45%. Increasing Cys improved FC that optimized at 0.40% with fast-feathering birds (quadratic, P < 0.01), whereas slow-feathering broilers were not responsive. Nitrogen retention measured from d 20 to 21 did not indicate a difference attributable to feathering but a Cys optimization at 0.43% with both broiler sources. Present experimentation indicates a Met requirement approximating 0.50% is appropriate for broilers 0 to 3 wk of age, regardless of feather rate; however, the estimated Cys requirement for slow-feathering males (0.39%) was less than for fast-feathering (0.44%) males.

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Available from: Edwin Moran, Jan 22, 2015
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    • "This model increased higher Thr requirements than those of broken-line models for growth performances 2. CP: 191.3 or 179.7g/kg feed for 0–3 weeks, 176.7 or 165.4g/kg feed for 3–6 weeks. Thr: 6g/kg feed for 0–3 weeks, 5.4g/kg feed for 3–6 weeks Performance Fatufe et al. (2004) 1. Depending on genotype 2. They diVered in lysine concentration from 3.8 to 16.8g/kg Performance Kidd et al. (2004) The 21–42 day threonine need across was estimated as 0.74% total or 0.65% digestible Feed intake is higher, but not in BW gain or breast meat yield Vieira et al. (2004) 1. Reducing diets with SAA/Lys of 77% impairs performance 2. Increasing diets with SAA/Lys of 77% was optimum Performance Corzo et al. (2003) 1.00% as required by NRC (1994) is in agreement Live production and meat yield are good, but carcass and skin are not Kalinowski et al. (2003) 0–3 weeks of age Performance 1. Met required is 0.50% 2. Cys required is 0.39% (slow-feathering males) and 0.44% (fastfeathering males) Sterling et al. (2003) The amino acid requirements of broilers are a constant proportion of CP levels Comment: Two levels of lysine per CP level (35 and 48 g lysine/kg CP) Chamruspollert et al. (2002) 1. Met requirement of male chicks needed to be higher than that of females, but not signiWcant 2. "
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